The liner is (i think) a wartime/postwar Finnish depot replacement. There is a marking inside (to the right) of the helmet. I think it is Q66 F. A nice used helmet in good condition. The item "GERMAN WW1 HELMET (USED BY THE FINNISH ARMY IN WW2)" is in sale since Tuesday, February 19, 2019.
This item is in the category "Collectables\Militaria\World War I (1914-1918)\Helmets/ Hats". The seller is "0400sukram" and is located in Vantaa. This item can be shipped worldwide.